NVA mild steel is a commonly used material in the shipbuilding industry.An accurate model for description of this material’s ductile fracture behaviour in numerical simulation is still a challenging task.In this pape...NVA mild steel is a commonly used material in the shipbuilding industry.An accurate model for description of this material’s ductile fracture behaviour in numerical simulation is still a challenging task.In this paper,a new method for predicting the critical void volume fraction fc in the Guson-Tvergaard-Needleman(GTN)model is introduced to describe the ductile fracture behaviour of NVA shipbuilding mild steel during ship collision and grounding scenarios.Most of the previous methods for determination of the parameter fc use a converse method,which determines the values of the parameters through comparisons between experi-mental results and numerical simulation results but with high uncertainty.A new method is proposed based on the Hill,Bressan,and Williams hypothesis,which reduces the uncertainty to a satisfying extent.To accurately describe the stress-strain relationship of materials before and after necking,a combination of the Voce and Swift models is used to describe the material properties of NVA mild steel.A user-defined material subroutine has been developed to enable the application of the new parameter deter-mination method and its implementation in the finite element software LS-DYNA.It is observed that the model can accurately describe structural damage by comparing the numerical simulation results with those of experiments;thus,the results demon-strate the model’s capacity for structural response prediction in ship collision and grounding scenario simulations。展开更多
This article shows genomic alignment methods using the classic“Needleman”and“Smith-Waterman”algorithms,the latter they were optimized by the ABC(artificial bee colony)algorithm.In the genomic alignment,a goal stat...This article shows genomic alignment methods using the classic“Needleman”and“Smith-Waterman”algorithms,the latter they were optimized by the ABC(artificial bee colony)algorithm.In the genomic alignment,a goal state is not presented,the experiments that are carried out show alternative alignments by ABC were proposed.Different types of alignments could exist within the classical algorithm,based on a horizontal,vertical,diagonal and inverse search mechanism on a match value table.Our ABC-Smith Waterman algorithm was generated from the genomic sequences written in rows and columns for the search for similarities that will provide values that ABC uses to process and provide more results of alignments that can be used by scientists for their experiments and research.展开更多
氨基酸序列的序列比对是研究蛋白的结构和功能关系的有力工具。本文利用Visual Basic for Applications的宏功能,采用Needleman-Wunsch算法在Excel中建立模型,对两条人类肿瘤抗体的氨基酸序列进行序列配联,找出它们的同源性。通过和一...氨基酸序列的序列比对是研究蛋白的结构和功能关系的有力工具。本文利用Visual Basic for Applications的宏功能,采用Needleman-Wunsch算法在Excel中建立模型,对两条人类肿瘤抗体的氨基酸序列进行序列配联,找出它们的同源性。通过和一些常用序列分析软件的比较,这种方法简单、直观和易于接受。展开更多
In this work, a set of GTN （Gurson-Tvergaard-Needleman） parameters of the Alloy52M dissimilar metal welded joint （DMWJ） have been calibrated, and a micromechanical analysis of in-plane constraint effects on the lo...In this work, a set of GTN （Gurson-Tvergaard-Needleman） parameters of the Alloy52M dissimilar metal welded joint （DMWJ） have been calibrated, and a micromechanical analysis of in-plane constraint effects on the local fracture behavior of two cracks, which located in the weakest regions of the DMWJ, has been investigated by the local approach based on the GTN damage model. The results show that the partition of the material and the variation of the q2 parameter make the J-resistance curves obtained by numerical simulations close to the experimental values. The numerical J-resistance curves and crack growth paths are consistent with the experiment results, which show that the GTN damage model can incorporate the in-plane constraint effect. Furthermore, after the stress, strain and damage fields at the crack tip during the crack propagation process have been calculated, and the change of the J-resistance curves, crack growth paths and fracture mechanism with in-plane constraint have been analyzed.展开更多
文摘NVA mild steel is a commonly used material in the shipbuilding industry.An accurate model for description of this material’s ductile fracture behaviour in numerical simulation is still a challenging task.In this paper,a new method for predicting the critical void volume fraction fc in the Guson-Tvergaard-Needleman(GTN)model is introduced to describe the ductile fracture behaviour of NVA shipbuilding mild steel during ship collision and grounding scenarios.Most of the previous methods for determination of the parameter fc use a converse method,which determines the values of the parameters through comparisons between experi-mental results and numerical simulation results but with high uncertainty.A new method is proposed based on the Hill,Bressan,and Williams hypothesis,which reduces the uncertainty to a satisfying extent.To accurately describe the stress-strain relationship of materials before and after necking,a combination of the Voce and Swift models is used to describe the material properties of NVA mild steel.A user-defined material subroutine has been developed to enable the application of the new parameter deter-mination method and its implementation in the finite element software LS-DYNA.It is observed that the model can accurately describe structural damage by comparing the numerical simulation results with those of experiments;thus,the results demon-strate the model’s capacity for structural response prediction in ship collision and grounding scenario simulations。
文摘This article shows genomic alignment methods using the classic“Needleman”and“Smith-Waterman”algorithms,the latter they were optimized by the ABC(artificial bee colony)algorithm.In the genomic alignment,a goal state is not presented,the experiments that are carried out show alternative alignments by ABC were proposed.Different types of alignments could exist within the classical algorithm,based on a horizontal,vertical,diagonal and inverse search mechanism on a match value table.Our ABC-Smith Waterman algorithm was generated from the genomic sequences written in rows and columns for the search for similarities that will provide values that ABC uses to process and provide more results of alignments that can be used by scientists for their experiments and research.
文摘氨基酸序列的序列比对是研究蛋白的结构和功能关系的有力工具。本文利用Visual Basic for Applications的宏功能,采用Needleman-Wunsch算法在Excel中建立模型,对两条人类肿瘤抗体的氨基酸序列进行序列配联,找出它们的同源性。通过和一些常用序列分析软件的比较,这种方法简单、直观和易于接受。
基金supported by the National Natural Science Foundation of China(Grant No.51605292)the Natural Science Foundation of Shanghai(Grant No.15ZR1429000)the Youth Foundation of Shanghai(Grant No.ZZslg15013)
文摘In this work, a set of GTN （Gurson-Tvergaard-Needleman） parameters of the Alloy52M dissimilar metal welded joint （DMWJ） have been calibrated, and a micromechanical analysis of in-plane constraint effects on the local fracture behavior of two cracks, which located in the weakest regions of the DMWJ, has been investigated by the local approach based on the GTN damage model. The results show that the partition of the material and the variation of the q2 parameter make the J-resistance curves obtained by numerical simulations close to the experimental values. The numerical J-resistance curves and crack growth paths are consistent with the experiment results, which show that the GTN damage model can incorporate the in-plane constraint effect. Furthermore, after the stress, strain and damage fields at the crack tip during the crack propagation process have been calculated, and the change of the J-resistance curves, crack growth paths and fracture mechanism with in-plane constraint have been analyzed.
